Regular Article

Theoretical Chemistry Accounts

, 132:1337

Open Access This content is freely available online to anyone, anywhere at any time.

Numerical investigation of the elastic scattering of hydrogen (isotopes) and helium at graphite (0001) surfaces at beam energies of 1 to 4 eV using a split-step Fourier method

  • Stefan E. HuberAffiliated withInstitute for Ion Physics and Applied Physics, Innsbruck University Email author 
  • , Tobias HellAffiliated withDepartment of Mathematics, Innsbruck University
  • , Michael ProbstAffiliated withInstitute for Ion Physics and Applied Physics, Innsbruck University Email author 
  • , Alexander OstermannAffiliated withDepartment of Mathematics, Innsbruck University

Abstract

We report simulations of the elastic scattering of atomic hydrogen isotopes and helium beams from graphite (0001) surfaces in an energy range of 1–4 eV. To this aim, we numerically solve a time-dependent Schrödinger equation using a split-step Fourier method. The hydrogen- and helium-graphite potentials are derived from density functional theory calculations using a cluster model for the graphite surface. We observe that the elastic interaction of tritium and helium with graphite differs fundamentally. Whereas the wave packets in the helium beam are directed to the centers of the aromatic cycles constituting the hexagonal graphite lattice, they are directed toward the rings in case of the hydrogen beams. These observations emphasize the importance of swift chemical sputtering for the chemical erosion of graphite and provide a fundamental justification of the graphite peeling mechanism observed in molecular dynamics studies. Our investigations imply that wave packet studies, complementary to classical atomistic molecular dynamics simulations open another angle to the microscopic view on the physics underlying the sputtering of graphite exposed to hot plasma.

Keywords

Surface scattering DFT Splitting method Magnetic fusion Plasma-wall interaction Time-dependent wave packet simulation